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प्रश्न
Comment on the role of placenta as an endocrine gland.
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उत्तर
Placenta acts as an endocrine gland and produces the human chorionic gonadotropins, human placental lactogen, oestrogen, progesterone and relaxin (later stages of pregnancy). These hormones support foetal growth and help in the maintenance of pregnancy. Hormones like oestrogen, progestogen, cortisol and prolactin are increased several folds in the maternal blood.
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संबंधित प्रश्न
Eye lens is formed from ______.
Which extra-embryonic membrane in humans prevents desiccation of the embryo inside the uterus?
The first movements of the foetus and appearance of hair on its head are usually observed during which month of pregnancy?
Mark the odd one.
Read the following and answer from given below:
Cleavage is the series of rapid mitotic divisions in the zygote and forms blastula. The 2, 4, 8, 16 daughter cells are called blastomeres. An embryo with 64 blastomeres is known as a blastocyst and has a blastocoel cavity. Blastocyst gets implanted in the uterine wall and leads to preganancy.
The solid mass of cells with 16 blastomeres is called ______
hCG is secreted by ______
Placenta is
Draw a diagram showing human foetus within the uterus and label any four, parts in it.
During embryogenesis in dicots, the zygote divides into a basal cell and a terminal cell. The basal cell divides repeatedly to produce a structure called suspensor. Carefully observe the image given below and describe the function of cell – A and cell – B of the suspensor.
Zygote
The diagram given below shows the early embryonic stages of fish, reptiles, birds and humans. Though adult reptiles, birds and mammals breathe air, their embryos possess gills. How does this fact support evolution?
